Threaded structure



Dec. 4 1923. 1,473,553

l c. P. MARYE THREADED STRUCTURE Original Filed Feb. l, 1919 5 fvwm-- 26P 5 i I 22 'A l-m ulmllumllllllm u mulllll out its entire length.

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raar ersten. i

CJIEEORD l?. MARYE, OF CHICAGO, ILLINOIS, ASSIGNO'R T0 MRYE SAFETY NUTCOR- PORTON, A CGBPORATON 03F ILLINQIS,

THREADED STRUCTURE.

` 9rig1na1 application led February 1 1919, Serial No. 274,447. Dividedand this application led February'2'6, 1921.

To @ZZ/whom# may concern:

Be it known that l, CLIFFORD P. MAME, a citizen of the United States,residing at Chicago, in the county of Cook and State of illinois, haveinvented certain new and useful improvements in Threaded Structures, ofwhich the following is a specication.

This invention relates to threaded' structures. l

lt will beexplained as applied to a selfloclring nut. Cne of the objectsof the inventionis to provide an improved self-locking threadedstructure.

Another object is to provide a thread which will provide a lockingaction through- Another object' is to provide a thread wherein thelocking action is evenly dis `1tributed throughout its active length.

Another object is to provide a self-locking threaded structure whichwill retain its locking properties after repeated application. anotherobject is to provide a structure which will lessen the wear ordistortion of both itself and the complementary threaded object withwhich it is used.

Another object is to provide a self-locking thread which may he producedby a milling operation.

Another object is to providel a structure wherein all of the threadconvolutions are alike.

Another object is to provide an improved self-locking nut.

@ther objects and advantages will hereinafter appear.

A This ap lication is a division of Serial No. 274,447, ti ed Februaryl, 1919. The former application relates particularly to and c aims amethod for producing nuts.

thread 4is a lcontinuous helix composed of parallel spiral convolutionsof uniform inclination or uniform axial advance-` In other` words thehelix angle of the thread' is constant. The development of the pitchline of such. a thread is a straight inclined line.

@n the other hand the improved self-lock ing thread is a continuoushelix composed The ordinary standard vtions of the nut thread deviateetually from Serial No. 447,935.

of yparallel spiral convolutions of continuously varying inclination oraxial advance. Inother words the helix angle of the self lockingthread'is continuously varying and the convolutions are parallel. Thedevelopment of the pitch line of this thread is a continuouslyundulating vor sinuous inclined line. When such a thread .is applied,i'or example, to a complementary standard thread the relativedisplacement produces a substantially uniformly distributed locking orgripping action.

The nut chosen outwardly an ordinary undistorted nut of standard form.In order to facilitate its applicationto a bolt it ma have a few of itsfirst or entering convolutions within the bore of greater internaldiameter than the rest of the convolutions.

T he. thread convolutions of the nut within' the active or locking zoneare alike and adtor illustration resembles i Vance or progress inparallelspirals of continuously varying inclination. ln other words thepitch line of the thread isa continuously undulating helix since therate'of axial advance is always changing.

When a nut provided with such an aber vrant thread is turned upon a bolthaving a.

complementary thread of standard form (a thread of uniform or truehelical advance) the relative displacement of the bolt and nut threadswill cause an abnormal frictional err gagement or binding actiontherebetween. The. thread of the nut will .tend to force the standardthread' of the bolt into an aberrant helix and the thread of the boltwill tend to force the thread of the nut into a true or uniformlyadvancing helix.

Since all of the active or locking convolua uniform spiral advance,` theockin action is substantially evenly distri uted throughout all of theconvolutions in contact with the bolt thread. Consequently to provide agiven locking eiiect, the action er convolution may be less than if theconvo utions deviated unequally.

A slight deviation from a uniform ad- Vance will provide a nut by whichsuiiicient transient and minute mutual distortion may be produced tolock the bolt and nut tolill? gether. 'lihe extreme minuteness of thenecessary distortion, resulting from the equal and gradual deviation ofthe aberrant thread, permits the nut to be removed and replaced a numberof times Without causing suflicient Wear or permanent distortion ofeither the bolt or the nut thread to destroy the locking action@ y l Anembodiment of the invention is illustrated in the accompanying drawing,Where- 1n- Fig. l is an enlarged diametrical section i of a self lockingnut embodying my invenorifice at one and the same time.

Cil

tion.

Fig. 2 is an elevation of a milling tool, such as may be used inproducing the nut, and

Fig. 3 is a diagrammatic View of a machine for making the nut.

rlhe nut 5 is provided with a'thread having two bolt-entrantconvolutions 6 and 7, somewhat larger in diameter than the convolutions8, but or' the same pitch and character as the convolutions of theremaining portion of the thread spiral. l he obi ect of this is topermit the bolt to enter freely into the nut and into threaded relationwith the nut orifice. The milling cutter 9, for cutting the thread inthe nut, is provided with a series of teeth such as l0, ll and l2, whichWill cut spirals of larger diameter than the teeth 13, 14 and l5, etc.The latter teeth are of the same diameter but ditl'er in diameter fromthe teeth l0, l1 and 12. All of the .teeth are,l however, of vthe sameseparation or pitch and character. The series of teeth 10, ll and 12will cutthe convolutions 6 and 7 of the nut, on the entrant sidethereof, While the remaining' teeth Will cut the convolutions in vthemain body of the nut.

To produce the aberrant thread in the orilice or bore of the nut, thecutter is rotated at a relatively hi h velocity to give it goed cuttinge-ect andg the nut is so presented to the cutter that the cutter Willcut all of the thread convolutions in one side of the nut After `thecutter has been set into rotatiom' at suitable velocity, the nut and thecutter are relatively moved with respect to each other in a direction atsubstantially right angles l-to their respective axes, so that the teethof the cutter will cut into the nut la distance requisite for the depthof the thread. After this has been done the nut and the cutter are thenrelatively moved about their axes, and coincidently are axially movedwith respect to each other to produce. and define the spiral or pitchline of the thread convolutions. lf the relative axial movement or helixangle is uniform or constantJ a standard nut having true s iraledconvolutions would he produced. lrowever, ythe locking nut is producedby continuously varying Ithe relative axial movement or helix angle7 sothat the hamaca thread whose convolutions form an aberrant helix. y

Machines of various kinds may be provided o'r producing the thread inthe orifice or bore of a blank nut. Merely for the purpose ofillustrating and explaininr the method of procedure a hand operate machine is shown in F ig. 3.

The cutter is rotated by a handle 22 through a gear Wheel 23 and apinion 2e. Pinion 24 is on a spindle or chuck which carries cutter 9.

The blank nut is held in a rotatable and axially and radially movablechuck 25. Chuck 25 is rotated by a handle 26.

The axial movement of the chuck is pro duced by the cooperation of a camgroove 27 in acam 28 and a relatively stationary pin 29. The groove is.cut into cam 28 as a helix of aberrant spiral configurationcorresponding to the desired variation in the pitch line of the thread.ln other Words? the axial advance of cam groove 27 is not uniformthrough its length but chang-es. When the chuck is rotated by handle 26,the

chuck is simultaneously advanced at a variable rate and thus the cuttingof the thread in the bore of the nut advances axially at a varying rateproducing the devia"y tion in the spiral pitch line of the threads dle31. This screw threads througi a poru tion of the machine trame and inbein turned2 advances or retracts the nut holding chuck radially. rl`hisadjustment is for the purpose of regulating the depth of the threads andfor forcing the nut into cutting position relative to the cutter.

The continuous thread developed in the nation and which constitute acontinuous helix.

2. A self-locking thread in which parallel spiral convolutions form acontinuous helix of continuously .varying axial advance.

3. A self-locking threaded object having a continuous thread consistingof several continuous thread in the Wall of the bore, convolutions ofuniform separation and said thread being composed of parallel 10 varyinghelix angle. spiral convolutions of oontinuously varying 4. A lock nuthaving a continuous thread inclination, 5 composed of several parallelspiral convolu- In testimony whereof I hereunto set my tions ofcontinuously varying inclination. hand.

5. A look-nut having a bore with an enlarged diameter adjacent one end,and a l CLIFFORD P. MARYE.,

